To evaluate the response of pile groups under lateral loading, a widely accepted approach is to use the curve of soil resistance, p versus local pile deflection, y (p-y curve) together with p-multiplier. The limiting force per unit length pu (limit of p) is often attained within a depth normally up to 8d (d = pile diameter), and the response of laterally loaded piles is generally controlled by the mobilized pu. Thus, determination of this pu is critical to a satisfactory prediction of the pile response. Various expressions have been developed previously for the pu. However, based on 70 field tests on single piles and 20 tests on pile groups, an extensive study conducted recently by the author and his team indicates that only three parameters are sufficient to describe the limiting force profile (LFP), while the parameters themselves may be modified to account for other factors. This paper addresses the effect of pile-head conditions, and group interaction on the LFP by comparing measured with predicted response of a few typical pile tests.